In addition to the newly approved lung disease drug Brin Supplement, which InsMed expects to be a blockbuster this year, the New Jersey company revealed trial results for its older lung disease drug Aricais, which could pave the way for a major label expansion.
The Phase 3b Encore study tested the antibiotic combination of inhaled Aricace and azithromycin and ethambutol versus the antibiotic combination plus a placebo in patients with newly diagnosed Mycobacterium avium complex (MAC) lung infections.
The study met primary and multiplicity-controlled secondary culture conversion endpoints, the company said in a March 23 release.
The Arikayce regimen demonstrated both statistically significant and clinically meaningful improvements in respiratory symptom score (RSS) and culture conversion rates.
Based on these results, InsMed plans to apply for an expanded indication in the second half of this year, which will allow it to be used in newly diagnosed patients who have not received antibiotics. Arikayce was first approved by the FDA for intractable diseases in 2018.
InsMed CEO William Lewis said in a conference call Monday that the expansion will significantly increase the number of patients Arikais can serve from 30,000 to 200,000. He added that he also hopes that the results of meeting the FDA’s post-marketing requirements will persuade the FDA to change its consent for ARIKAYCE from early to full.
“This is a particularly difficult disease to treat,” Lewis says. “All of the other companies that have tried to develop new drugs have failed to produce clinical trial results sufficient for approval in double-blind trials. I think this only highlights the dire need for this patient population.”
The result sent Insmed’s stock price up 7% on Monday morning.
Regarding the primary endpoint, patients in the ARIKAYCE treatment group gained an average of 17.8 points from baseline on the RSS scale after 13 months, compared to an average increase of 14.7 points in the placebo group.
The key secondary endpoint was sputum culture conversion rate measured at different time frames. After 13 months, a statistically significant proportion of Arikayce patients achieved acculturation (82% vs. 56%).
After 15 months, a statistically significant proportion of Arikayce patients achieved sustained culture conversion (76% compared with 48% in the control group). Similar culture conversion rates were evident for all measurement periods from month 1 to month 15 (PDF).
Lewis said the results were “remarkable” evidence of Arikais’ ability to improve outcomes for MAC patients during the early stages of treatment. He compared results from Insmed’s previous treatment trial, which showed culture conversion in about a third of patients.
“What’s important to note here is that the data from this study is unambiguously positive from the perspective of physicians seeking to eradicate evidence of infection in their patient populations,” Lewis said. “The data suggest there is a strong incentive to treat these patients early, and lower dropout rates will reduce the burden of treatment on patients.”
The active ingredient in the antibiotic Aricais is amikacin, a 20-year-old antibiotic that was initially administered intravenously until InsMed developed an inhaled formulation to treat MAC, a potentially fatal condition diagnosed in more patients in Japan than in the United States.
In 2025, Arikayce’s revenue increased by 19% to $434 million. Mr. Lewis said he would reveal later how the potential expansion would affect peak sales.
